in reply to Re^3: The Deceiver
in thread Why does a Perl 5.6 regex run a lot slower on Perl 5.8?

To add few bits to your list,

... RedHat ships with badly packaged Tcl/Tk, (this was discussed in Tcl::Tk module development list and this makes supporting of Tcl::Tk considerably harder on RedHat)

In Section Meditations